CHAPTER 11

This is the revision page for chapter 11. In this chapter, you learn how to find areas in regular and irregular shapesand how to calculate volume and capacity. This web page will walk you thruogh each exercise, complete with examples and diagrams. With a little help from me, you will be sure to pass this part of the exam. Get your notes and start revising!




11.1 - AREA

Think about the following questions:

  • How big is your room?

  • how many tiles do you need to tile your kitchen and bathroom?

  • how much paint do you need to paint your house?

these questions require you to find area. if 1 square in the shape below equals one square unit,

then we can count the squares to calculate the perimeter and the area.


nov-squares.jpg

Question: count the squares in the shape to determine the area

Working Out: start from the top - left hand corner and count the squares

Answer: 25 square units (dont forget to add the units on the end!)



Question: count the squares in the shape to determine the perimeter

Working Out: start from the top - left hand corner and count the squares clock-wise around the shape

Answer: 20 square units (dont forget to add the units on the end!)



here is some extra help:

  • mm: used to measure very small shapes

  • cm: used to measure small shapes

  • m: used to measure large shapes i.e a basketball court

  • km: used to measure large areas i.e land, countries

  • ha: used to measure the area of land






11.2 - AREA OF A RECTANGLE

to find area, you times the width by the length. e.g:

image001.pngYou times the length by the width, and there is your answer!

Don't forget to add the units on the end of your answer or your answer won't count!

Also, you should start to get the hang of using formulas. here is what you do:

length is L, width is W and A is area you write down A= L x W at the start of each question!

Question: Find the area of this shape

Working Out: 100x200=20000

Answer: (l x w) 20000m2












11.3 - AREA OF SHAPES BASED ON RECTANGLES

here is the most confusing part of the chapter. take a look at the example below.

sapec123.jpg


a) look at the size of the sides if the shape

cut the shape into smaller shapes (cut it to your advantage so you

don't have to do more work)

in this case, times 2 by 6, and 4 by 5

add them together

there's your answer!

dont forget the units or the formula!

(hint: formula is still the same as before and it will be like that for all 2D quadriatrials)

b) in this case, times 9 by 14 and 7 by 3

minus 7 times 3 from 9 by 14

there's your answer!

don't forget the units or formula!

11.4 - AREA OF A TRIANGLE

The area of a triangle is pretty straight forward. you times the base by the height, and halve it.

the formula is A= 1/2 x B x H (area1/2 x base x height) and you still need to include the units in your answer too.

sapec124.jpg

11.5 - VOLUME

Volume is a measure of space that a 3D object takes up. it is measured in cubic units. the formula forcubic measurement is V = x W x D

sapec125.jpg

Ex 9: count the cubic units on the top layer

times them by how many layers there

Ex 10: times 6 by 3 by 5


11. 6 - CAPACITY

Capacity is what a container can hold. You need to convert the volume to a more suitable form of measurement.

here is the conversion chart:

sapec126.jpg

dont forget the units in your answer!

REVISION
QUESTIONS
Q 1 Find the area of a square with a side length of 16m
Q 2 Find the perimeter of a square with an area of 9 cm2
Q 3 Find the number of squares in the shape below

nov-squares.jpgQ 4 What is the area of a rectangle with a length of 16 cm and a width of 4 cm?
a) 26
b) 46
c) 64
d) 84
Q 5 Find the area of a rectangle with a length of 22 cm and a width of 13 cm
Q 6 find the area of a triangle that has a height of 2 m and has a base of 8 m
Q 7 Find the volume of a rectangular prism with a depth and length of 5 cm and a width of 9 cm
Q 8 Find the volume of a rectangular prism with a depth and length of 18 cm and a width of 1 cm
Q 9 Find how many millilitres of water a container with the dimensions of a length of 5 cm, a width of 7 cm and a a depth of 2 cm
Q 10 Find the area of a square with a side length of 666cm





answers Q1 - - - - - - -(l x w) 64 cm
Q2 - - - - - - -12 cm
Q3 - - - - - - -25
Q4 - - - - - - -c
Q5 - - - - - - -(l x w) 286 cm
Q6 - - - - - - -(l x w x 1/2) 8 m
Q7 - - - - - - -(l x w x d) 225 cm
Q8 - - - - - - -(l x w x d) 324 cm
Q9 - - - - - - -(l x w x d) 70ml
Q10 - - - - - - (l x w) 2664 cm